A Solar-powered Drone That can Fly Forever?

INTERESTING ENGINEERING SHOP

Scientists in China have developed a drone that can fly continuously as long as the sun is out. But what could such a machine be used for? The researchers believe it could be used for remote monitoring operations where long-distance flight is required.

Speaking of machines that stay aloft for extended periods of time, we have some exciting satellite tech to tell you about. Also in China, the state-owned China Aerospace Science and Technology Corporation (CASC) recently announced its all-electric satellite propulsion satellite, the APStar-6E, is fully operational. 

The satellite industry is booming, so let’s take a look at some of the most impressive satellite propulsion innovations of recent months and years.

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AEROSPACE ENGINEERING SPOTLIGHT

A solar-powered drone for remote monitoring

A team of researchers has developed an ultralightweight solar-powered drone that can perform unlimited flight during the daytime. 

The drone, called ColumbFly, weighs only 4 grams. It uses a solar cell to generate electricity. 

The team behind the new technology, from Beihang University in Beijing, said each component was carefully chosen. They took great care to balance the aircraft’s efficiency and weight for optimal flight.

That cell creates an electric field between oppositely charged plates arranged in a circle. The opposing charges act like repelling magnets, producing enough force to turn the rotor blades. This generates torque, allowing the drone to fly.

Impressively, it can fly continuously without having to land—until the Sun goes down, that is. This is because it has a high lift efficiency of 30.7 grams per watt and a very light power system that uses only 0.568 watts. It generates 920 watts per square meter.

ColumbFly is a type of micro aerial vehicle (MAV). MAV’s have traditionally had very short flight times – around 10 minutes for vehicles weighing less than 10 grams. This is due to the limitations of small batteries and solar cells. 

The team developed a drone with a motor that features an inner ring of stationary charged plates, or stators. These are made out of thin carbon-fiber plates coated with aluminum foil. Adjacent stator plates carry opposing charges and are surrounded by a ring of 64 rotating plates. 

The motor’s activation occurs when the outer ring plates are charged, initiating attraction between opposite stator plates and setting the rotation in motion.

As the stator and rotor plates closely align, thin wires make contact, allowing charge to transfer and equalize and converting attraction to repulsion. This sustains rotor movement, allowing prolonged flight.

AERO BULLETIN

4 impressive satellite propulsion systems

The satellite boom continues unabated, with companies like SpaceX and Rocket Lab regularly launching large constellations into orbit. 

And it’s not only the launch companies that innovate; here are some of the most impressive recent satellite propulsion innovations.

CASC’s all-electric propulsion system

The China Aerospace Science and Technology Corporation (CASC) this week announced it has completed in-orbit tests of its all-electric propulsion satellite. Asia-Pacific-6E, or the APStar-6E, is now fully operational.

Developed for operations in geosynchronous orbit, the satellite is the first based on the electrically propelled DFH-3E platform.

Fuel-free ‘air-breathing’ propulsion

Catalan company Kreios Space is developing a fuel-free propulsion system for very low Earth orbit (VLEO) satellites. The company’s system absorbs air—there is still some air at VLEO altitudes—to generate plasma. This plasma is then accelerated through an IPT thruster and electromagnetic nozzle.

“Right now, very low Earth orbit is an unused orbit simply because of the lack of propulsion systems capable of staying in this orbit,” Jan Mataró, Kreios Space CTO told IE in a recent interview. 

One of the key benefits of operating in VLEO is that satellites will reenter Earth’s atmosphere once their mission is over. No space debris can exist in VLEO, due to atmospheric drag. The orbit could also allow a massive increase in resolution for satellite images, due to their relative proximity to Earth.

Solar propulsion systems

The Planetary Society’s LightSail2 mission in 2019 showed that light sail propulsion was a feasible method for raising the orbit of a small satellite. All they used was a 32-square-meter (244-square-foot) sail made out of mylar to raise a small CubeSat spacecraft’s orbit by 1.9 miles (3.2 km).

The technology has already been incorporated into several NASA missions, and it could be used by commercial CubeSat missions to keep their small satellite in orbit just a little bit longer.